The invention relates to a transport installation comprising:                at least one carrier vehicle resting on the ground to move longitudinally in to-and-fro manner along a single running track,        two end terminals connected by the running track,        at least one crossing area where the running track is locally split into two laterally offset branches each respectively associated with outgoing movement and return movement of the carrier vehicle,        at least one pair of main support units carried by the carrier vehicle,        and two guiding elements arranged along the track to guide the carrier vehicle laterally in cooperation with the main support units, and each following one of the lateral branches in continuous manner.        
Such a transport installation with a passive carrier vehicle made to run along the running track by possibly reversible securing to hauling ropes running in opposite directions is known for example from the document EP1193153B1. But the disclosed solution does not make mention of the means implemented to guide the carrier vehicles along one branch during outgoing movement and along the other branch during return movement. Such an organization of the carrier vehicles does however represent a real problem.
A first solution for guiding a carrier vehicle along a running track, known for example from the document FR2500799, consists in permanent clamping of a guide buckling arranged in continuous manner along the track. But the permanent nature of the guiding link between the carrier vehicle and the buckling of the track does not enable the carrier vehicles to be guided along one branch during outgoing movement and along the other branch during return movement.
A second solution consists in providing at least one guiding elements arranged along the track and comprising a mobile section on entry and on exit from the crossing area, acting like a points switching system. But this solution remains problematic as it is very cumbersome and implements moving parts arranged on the track, rendering the latter liable to be damaged and constituting sources of danger.